Both theoretically and anecdotally, we know that dark mode makes a difference to phone batteries. Apps that change their default background hue to black rather than white just seem to last longer, and that logically makes sense – on OLED phones at least.
Now we have proof in the theoretical pudding. YouTube channel PhoneBuff has conducted a pretty conclusive test using two brand new iPhone XS Max handsets. Both handsets were set to 200cd/m2 brightness, and then robots ran through automated tests using four apps with dark modes. Two hours of Messages with another chatbot, two hours of mindlessly scrolling through Twitter, two hours of YouTube (in portrait mode), and two hours of Google Maps.
Related: How to enable Android dark mode
As you can see from the video embedded above, the differences at each point are pretty stark. After the chat test, the dark mode iPhone is at 88% battery to the light mode’s 83%, while the Twitter round is even more clear at 72% vs 57%. YouTube took things to 43% vs 20% and the Maps challenge killed the light mode model at an hour and 33 minutes. The dark mode version, however, made it all the way through to hit 26% battery at the end of the tests.
Related: OLED vs LED
At different brightnesses, the results were the same, albeit more severe for brighter settings and less significant at lower. At 100cd/m2 the Twitter test was a 5% difference, while at 300cd/m2 it was 12%.
Your mileage will vary, of course. Not only are dark mode-supporting apps in the minority, but this should only make a difference if your phone’s screen is AMOLED where pixels are shut off when black is replicated on screen. If your handset has an LED screen, you’re unfortunately out of luck.
Have you noticed improved battery life since switching to dark mode? Let us know on Twitter: @TrustedReviews.